Observability & SRE
Structured logging, metrics, tracing, health checks, and SLO-friendly instrumentation.
How to Mock HTTP Client Latency in Python
Simulate outbound HTTP request latency with configurable ranges to test timeouts, retries, and SLO monitoring without external services.
import time
import random
def mock_latency(host: str, min_ms: int = 100, max_ms: int = 500) -> dict:
"""Simulate an outbound HTTP request with mock latency."""
latency_ms = random.randint(min_ms, max_ms)
start = time.perf_counter()
time.sleep(latency_ms / 1000)
elapsed_ms = (time.perf_counter() - …
How to Simulate Trace Sampling Head in Python
Simulate head-based probabilistic trace sampling on mock trace data with a configurable sample rate and optional seed for reproducibility.
import random
def trace_sampling_head(mock_traces, sample_rate=0.5, seed=None):
"""Simulate probabilistic trace sampling (head-based) on mock data.
Args:
mock_traces: list of trace dictionaries with a unique 'trace_id'
sample_rate: float 0.0-1.0, probability of keeping a trace
see…
How to Use Log Levels DEBUG INFO WARNING ERROR in Python
Demonstrates Python's logging levels (DEBUG, INFO, WARNING, ERROR) with basicConfig and a logger, showing how severity filtering controls output.
import logging
# Configure a mock logger to demonstrate log levels
logging.basicConfig(level=logging.DEBUG, format="%(levelname)s: %(message)s")
logger = logging.getLogger("mock_logger")
# Simulate events at each severity level
logger.debug("Detailed diagnostic info")
logger.info("General system operation")
logger.w…
How to mock Prometheus alert rule thresholds in Python
Simulate a Prometheus alert rule with a configurable threshold and duration window, firing only when the metric exceeds the threshold long enough.
import time
import random
class MetricsStore:
def __init__(self):
self.metrics = {}
def set_metric(self, name, value, labels=None):
key = (name, tuple(sorted((labels or {}).items())))
self.metrics[key] = value
def get_metric(self, name, labels=None):
key = (name, tuple(s…
Mock Health Endpoint Liveness Check in Python
Simulate a liveness endpoint that reports service health with a configurable failure rate and uptime.
import time
import random
def liveness_check(service_name: str, failure_rate: float = 0.1) -> dict:
"""Mock health check that returns liveness status with a configurable failure rate."""
healthy = random.random() > failure_rate
response = {
"service": service_name,
"status": "alive" if he…
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Observability & SRE — Python code examples
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